/*
 * Copyright 2017 ~ 2025 the original author or authors. <wanglsir@gmail.com, 983708408@qq.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.wl4g.devops.dguid.baidu.utils;

import java.lang.Thread.UncaughtExceptionHandler;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicLong;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;

/**
 * Named thread in ThreadFactory. If there is no specified name for thread, it
 * will auto detect using the invoker classname instead.
 * 
 * @author yutianbao
 */
public class NamingThreadFactory implements ThreadFactory {
	private static final Logger LOGGER = LoggerFactory.getLogger(NamingThreadFactory.class);

	/**
	 * Thread name pre
	 */
	private String name;
	/**
	 * Is daemon thread
	 */
	private boolean daemon;
	/**
	 * UncaughtExceptionHandler
	 */
	private UncaughtExceptionHandler uncaughtExceptionHandler;
	/**
	 * Sequences for multi thread name prefix
	 */
	private final ConcurrentHashMap<String, AtomicLong> sequences;

	/**
	 * Constructors
	 */
	public NamingThreadFactory() {
		this(null, false, null);
	}

	public NamingThreadFactory(String name) {
		this(name, false, null);
	}

	public NamingThreadFactory(String name, boolean daemon) {
		this(name, daemon, null);
	}

	public NamingThreadFactory(String name, boolean daemon, UncaughtExceptionHandler handler) {
		this.name = name;
		this.daemon = daemon;
		this.uncaughtExceptionHandler = handler;
		this.sequences = new ConcurrentHashMap<String, AtomicLong>();
	}

	@Override
	public Thread newThread(Runnable r) {
		Thread thread = new Thread(r);
		thread.setDaemon(this.daemon);

		// If there is no specified name for thread, it will auto detect using
		// the invoker classname instead.
		// Notice that auto detect may cause some performance overhead
		String prefix = this.name;
		if (StringUtils.isEmpty(prefix)) {
			prefix = getInvoker(2);
		}
		thread.setName(prefix + "-" + getSequence(prefix));

		// no specified uncaughtExceptionHandler, just do logging.
		if (this.uncaughtExceptionHandler != null) {
			thread.setUncaughtExceptionHandler(this.uncaughtExceptionHandler);
		} else {
			thread.setUncaughtExceptionHandler(new UncaughtExceptionHandler() {
				@Override
				public void uncaughtException(Thread t, Throwable e) {
					LOGGER.error("unhandled exception in thread: " + t.getId() + ":" + t.getName(), e);
				}
			});
		}

		return thread;
	}

	/**
	 * Get the method invoker's class name
	 * 
	 * @param depth
	 * @return
	 */
	private String getInvoker(int depth) {
		Exception e = new Exception();
		StackTraceElement[] stes = e.getStackTrace();
		if (stes.length > depth) {
			return ClassUtils.getShortName(stes[depth].getClassName());
		}
		return getClass().getSimpleName();
	}

	/**
	 * Get sequence for different naming prefix
	 * 
	 * @param invoker
	 * @return
	 */
	private long getSequence(String invoker) {
		AtomicLong r = this.sequences.get(invoker);
		if (r == null) {
			r = new AtomicLong(0);
			AtomicLong previous = this.sequences.putIfAbsent(invoker, r);
			if (previous != null) {
				r = previous;
			}
		}

		return r.incrementAndGet();
	}

	/**
	 * Getters & Setters
	 */
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public boolean isDaemon() {
		return daemon;
	}

	public void setDaemon(boolean daemon) {
		this.daemon = daemon;
	}

	public UncaughtExceptionHandler getUncaughtExceptionHandler() {
		return uncaughtExceptionHandler;
	}

	public void setUncaughtExceptionHandler(UncaughtExceptionHandler handler) {
		this.uncaughtExceptionHandler = handler;
	}
}